Gear grinding machine



April 14, 1970 A. B. BASSOFF 3,505,753

GEAR GRINDING MACHINE Filed April 18, 1967 2 Sheets-Sheet 1 mvsmon THpR a. BASSOFF ATTORNEYS April 14, 1970 A. B. BASSOFF GEAR GRINDING MACHINE 2 Sheets-Sheet 2 Filed April 18. 1967 ,kN TO w wvm m% A l VA ,4 T A ma/w Br w Y NM H V T United States Patent O 3,505,763 GEAR GRINDING MACHINE Arthur B. Bassotf, Oak Park, Mich., assignor, by mesne assignments, to Lear Siegler, Inc., Santa Monica, 'Calif.,

a corporation of Delaware Filed Apr. 18, 1967, Ser. No. 631,777 Int. Cl. 1324b 5/00 US. Cl. 51-52 20 Claims ABSTRACT OF THE DISCLOSURE A machine for grinding relatively large gears in which the gear is mounted on the frame for rotation only, the grinding wheel is reciprocated back and forth to grind the gear teeth, camming means or provided for rotating the gear to compensate for helix angle, to provide crowning if desired, and to provide for grinding one side of a tooth at a time, the wheel column being independently movable to an end of the frame for coaction with a vertically movable wheel trimmer.

SUMMARY OF THE INVENTION In accordance with the present invention the gear grinder is designed for relatively large gears and accordingly, it is desired to avoid an arrangement in which the gear has to be reciprocated in a direction parallel to its axis. On the other hand, the teeth of the gear may be helical and accordingly, it is essential that the grinding wheel, which is repricated parallel to the axis of the gear, be angularly adjustable in accordance with the gear helix. It is further desired to provide means for effecting rotation of the gear in accordance with the travel of the grinding wheel to compensate for helix. It is also possible, if desired, to provide for imposing additional back and forth rotation on the grinding Wheel in timed relation to traverse of the grinding wheel to provide for crowning the teeth of the gear. Finally, it is desired to provide for slight forward and reverse rotation of the grinding wheel to engage one side or the other of the tooth space being ground.

The means for effecting timed rotation of the gear comprises essentially a slide assembly movable on the base parallel to the direction of movement of the wheel column. However, it is desirable to be able to move the wheel to the end of the base for trimming and during this movement of the wheel column the cam assembly need not be caused to move with the wheel column. For this purpose, separate traverse devices in the form of piston and cylinder devices are provided and when one of these is in operation, the cam assembly is mechanically coupled to the wheel column so as to partake of its traverse.

It is accordingly an object of the present invention to provide a grinder for grinding relatively large gears including helical gears, and to provide means for selectively crowning the teeth of the gear in a simple operation in which the grinding traverse is accomplished by traverse of the grinding wheel while the work gear is moved only in rotation.

It is a further object of the present invention to provide a grinder of the class described including camming or sine bar and crowning mechanism slidable on the base, means for selectively coupling the assembly to the wheel support column, a first traverse unit for effecting simultaneous traverse both of the wheel support or column and the camming or sine bar assembly, and a second traverse device for effecting traverse only of the Wheel column or support.

Other objects and features of the invention will become apparent as the description proceeds, especially when taken in conjunction with the accompanying drawings, illustrating a preferred embodiment of the invention.

3,505,763 Patented Apr. 14, 1970 BRIEF DESCRIPTION OF THE DRAWINGS FIGURE 1 is a fragmentary perspective view of the grinder constructed in accordance with the present invention, with parts broken away.

FIGURE 2 is an enlarged fragmentary perspective view of certain details of the work support and work rotating mechanism.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings, the grinder comprises a relatively large stationary base 10, provided thereon with longitudinally extending ways 12 which may be continuous as shown or which may be provided in two sections for the independent slidable mounting of camming or sine bar mechanism and the wheel support or column. Mounted at the front of the base 10 and preferably longitudinally adjustable thereon in ways (not shown) is work support means comprising a tailstock 14 and a headstock 16 including conventional index mechanism (not shown), and means for mounting a work support shaft or spindle 18 to extend between the headstock and tailstock as suggested in FIGURE 1.

A grinding wheel support or column 2t] is provided for movement along the ways 12 provided on the base 10. At the front of the column 20 is a bracket 22 mounted for vertical adjustment on the column by suitable means such for example as the guide indicated at 24. Secured to the underside of the bracket 22 is a grinding wheel W connected by a. suitable shaft to a drive motor 28, the grinding wheel and motor being guided for angular adjustment about a vertical axis by adjustable support means indicated at 30. Angular adjustment of the grinding wheel takes place about a vertical axis passing centrally through the grinding wheel and is for the purpose of setting the wheel at the appropriate angle to cooperate with helical teeth on a work gear G.

It will be appreciated that in order to effect grinding of the teeth of the gear G, the wheel column 20 is reciprocated parallel to the ways 12 and the means for accomplishing this reciprocation constitutes a piston and cylinder traverse device 32 including a piston rod 34 coupled to a lead slide 36. The lead slide 36 is in turn mechanically coupled to the wheel column 20 by a member 38 which is internally threaded at its left end as seen in FIGURE 1. The member 38 is adapted to be coupled to the wheel column 20 by means of a plunger 40 vertically movable by a piston and cylinder device 42, the plunger 40 having a recess at its bottom engageable over a reduced portion 44 of the member 38.

The lead slide 36 carries a rotatable tubular shaft 46 having a threaded head 4-8 at its inner end. A rod 50 has a threaded head 52 and extends through the tubular shaft 46. The rod 50 is keyed to the shaft 46 by means indicated as a pin and slot connection 54. The member 38 has a longitudinally extending groove receiving a key 56 which prevents rotation of the member 38.

When it is desired to vary the spacing between the lead slide 36 and the wheel column 20, a jam nut 58 is loosened and hand wheel 60 is rotated, thus effecting relative longitudinal adjustment between the tubular shaft 46 and member 38. When the desired adjustment has been accomplished the jam nut 58 is tightened, drawing the threaded head 52 of the rod 50 toward the threaded head 48 of the tubular shaft 46, thus effecting a frictional lock with the threads at the interior of the member 38.

When it is necessary to trim the grinding wheel W a piston and cylinder device 42 is actuated to lift the plunger 40 and thereby to uncouple the wheel column 20 from the lead slide 36. A second piston and cylinder device 62 is provided having a piston rod 64 secured to the wheel column 20. The device 62 provides for very substantial movement of the wheel column and permits the grinding wheel W to be moved into a position directly over a trimmer indicated generally at 66 and having a movable trimming element or diamond 68 thereon. The wheel trimmer or dresser 66 is vertically movable with a platform 70 which may be moved vertically by suitable means such for example as a feed screw (not shown) and a hand wheel 72. In operation, when the wheel requires dressing, the wheel column is traversed into position adjacent the diamond 68 and is fed downwardly by an amount sufficient to provide stock for trimming. Thereafter, the trimming operation takes place and the wheel is returned to its operating position. Since the trimming takes place at the bottom of the wheel, the relationship between the trimmed wheel and the gear G is not disturbed by the trimming operation.

In order to provide for the proper rotation of the gear G the structure illustrated in detail in FIGURE 2 is provided. The work spindle 18 or an extension thereof, may be indexed by suitable index mechanism carried by the headstock 16 and the required timed back and forth rotation of the gear G is provided by means of a rack 74 in mesh with a pinion 75 carrier by the shaft or spindle 18. The rack 74 is movable with a transverse slide 76 and is movable relative to the slide by means of ways indicated at 78. Relative motion between the rack 74 and the slide 76 is provided by a pin 80 carried by a follower 82 movable in an inclined slot 84 formed in a block 86 movable transversely of the slide 76. The block 86 is connected to a small piston and cylinder device 88 and the amount of movement permitted the rack 74 relative to the slide 76 is determined by an adjustable stop nut 90 carried by a screw 92 fixed to the rack 74. When the piston and cylinder device 88 is actuated in one direction, abrupt movement of the rack 74 provides a small increment of rotation to the gear G, thus moving one side of a tooth space into engagement with the grinding wheel. In order to grind the other side of the tooth space, the piston and cylinder device 88 is actuated in the opposite direction.

In order to provide for the proper timed rotation of the gear G as the grinding wheel is traversed back and forth parallel to the axis of the gear, a sine bar 94 is provided having a slot 96 in which a slide block 98 is movable. The slide block 98 carries a pin 100 received in a cylindrical opening in the slide 76. The sine bar 94 is mounted for angular adjustment about a vertical axis coincident with the pin 100 by an adjustable plate 102 which is adapted to be angularly adjusted and secured in position by locking means such for example as nuts 104 engaging T-bolts 106 and movable in a circular T-slot in a crowning slide 108.

With the mechanism as thus far described it will be apparent that as the piston and cylinder device 32 is actuated, the slides 36, 108 and the sine bar 94 will be reciprocated parallel to the axis of the work spindle 1 8. This traverse or reciprocating movement of the sine bar 94 results in movement of the block 98 in the slot 96 and with corresponding traverse movement of the slide 76. This in turn carries the rack 74, resulting in rotation of the pinion 75, the spindle '18, and the work gear G.

The foregoing operation will result in the production of uncrowned gear teeth. However, present gear production normally requires that crowned profiles be provided on the teeth of ground gears. A crowned profile is the result of modifying the profiles of gear teeth longitudinally from end to end in a uniform manner so as to produce teeth which are thickest at an intermediate point and whose thickness gradually diminishes toward the end of the teeth.

In order to provide for crowning with the present gear finishing machine, there is provided a crowning cam 110 which is rotatable between roller followers 112 and 114 carried on pins 116 fixed to the crowning slide 108. The

carn* is mounted for rotation on a shaft .'118 to which is afiixed a crank arm 120 having a follower 122 movable in a slot 124 of a crowning cam sine bar 126. The sine bar 126 is mounted for adjustment by a circular plate 128 angularly adjustable about a vertical axis passing through the shaft 118, and is adapted to be clamped in place by T -bolts and nuts, as indicated at 130.

The crowning cam 110 is shaped so that its transverse dimension extending through the axis of the shaft 118 is uniform with the result that as the crank arm 120 is moved to rotate the cam 110, the followers 112 and 114 move at all times to maintain firm engagement with the cam.

It will of course be understood that rotation of the cam 110 produces a transverse movement of the crowning slide 108 relative to the slide 36 and this in turn results in shifting the lead sine bar 94 in a direction perpendicular to the axis of the work spindle 18.

It will further be understood that when crowning takes place, it is possible only to crown one side of a tooth at a time since the crowning motion, superimposed on the lead compensation motion, which produces the desired crown at the side of a tooth space, would not produce a similar crown at the opposite side. Accordingly, when crowning takes place the motion-limiting abutment or stop nut 90 and the piston and cylinder device 88 are employed to effect shifting after one or more strokes of the grinding wheel.

It will be apparent that the work gear G may be mounted between the head and tail stocks ad stock divided into exact required registration with the grinding wheel W by appropriate adjustment of the hand wheel 60.

It will further be apparent that simplified means are provided eifective for dressing the grinding wheel at frequent intervals as is required without disturbing the setup and without requiring any accuracy in feeding of the wheel prior to trimming. Inasmuch as in operation the gear is mounted between relatively heavy head and tail stocks, it is possible to support massive gears in the simplest possible manner without subjecting the machine to the stresses which would result if the gear were required to partake of traverse in addition to its rotation.

The drawings and the foregoing specification constitute a description of the improved gear grinding machine in such full, clear, concise and exact terms as to enable any person skilled in the art to practice the invention, the scope of which is indicated by the appended claims.

What I claim as my invention is:

1. A machine for grinding gears comprising a base,

a rotatable work support mounting a Work gear for rotation in a fixed position on said base.

a grinding wheel support reciprocable longitudinally on said base in traverse strokes parallel to the axis of said work support,

means for adjusting said wheel support about an axis perpendicular to the axes of said wheel support and work support in accordance with the helix angle of a work gear,

and lead mechanism connected to said work support and responsive to traverse of said wheel support to rotate said work support in timed relation to traverse of said wheel support.

2. A machine as defined in claim 1 in which said lead mechanism comprises a lead slide movable on said base in unison with said wheel slide, and

an adjustable sine bar and follower connected between said lead slide and said work support.

3. A machine as defined in claim 2, said lead mechanism comprising a rack and pinion connected between said sine bar and follower and said work support.

4. A machine as defined in claim 2 comprising adjustable means for connecting said lead slide to said slidable Wheel support and to vary the spacing therebetween.

5. A machine as defined in claim 2 comprising crowning mechanism repsonsive to traverse of said wheel support connected to said work support operable to rotate said work support back and forth during a single stroke of traverse of said wheel support, said mechanism being connected to said sine bar mechanism to effect movement of both said sine bar and follower as a unit.

6. A machine as defined in claim 5, said crowning mechanism comprising a crowning slide movable transversely of the direction of movement of said lead slide, a crowning cam connected between said base and crowning slide, and means for rotating said cam in accordance with traverse of said wheel support.

7. A machine as defined in claim 6 in which one of said slides is carried by the other of said slides for movement relative thereto in a direction transverse to the direction of movement of said other slide.

8. A machine as defined in claim 6 in which said lead slide is mounted on said base for movement parallel to the traverse movement of said wheel support, said crowning slide is mounted on said lead slide for movement perpendicular to the direction of movement of said lead slide, and one element of said sine bar and follower is mounted on said crowning slide.

9. A machine as defined in claim 8 comprising incremental gear rotating means operable to superimpose a predetermined increment of rotation to said gear support to provide for selective grinding of either side of a tooth space.

10. A gear grinding machine comprising a base,

a rotatable work support mounting a work gear for rotation in a fixed position on said base,

a grinding wheel support movable on said base in traverse strokes parallel to the axis of said work support, and

crowning mechanism comprising means responsive to traverse of said wheel support and connected to said work support to impose slight back and forth rotational movement on said work support in timed relation to traverse strokes of said wheel support.

11. A machine as defined in claim 10 comprising incremental gear rotating means connected to said work support operable to superimpose selective incremental rotational adjustment on said work support to provide for crowning only a single side of a gear tooth at a time.

12. A machine as defined in claim 10, said crowning mechanism comprising a crowning slide movable on said base perpendicular to the direction of traverse of said wheel support, cam means comprising a rotary crowning cam and a pair of opposed cam followers engaging opposite sides of said cam, said cam having a constant diameter between said followers, said cam means being connected between said base and said cam slide, means responsive to traverse of said wheel support effective to rotate said cam, and means connecting said cam means to said work support to rotate said work support in timed relation to traverse strokes of said wheel support.

13. A machine as defined in claim 12 comprising incremental gear rotating means operable to superimpose a predetermined increment of rotation to said gear support to provide for selective grinding of either side of a tooth space.

14. A machine as defined in claim 13 in which the means connecting the cam means to said work support comprises a rack and pinion, a movable carrier for said rack, and said incremental gear rotating means comprises means mounting said rack for limited longitudinal movement relative to said carrier, abutments acting between said rack and carrier to determine said limited relative movement therebetween, and means for selectively biasing said rack into engagement with one or the other of said abutments to superimpose incremental rotational movement of said pinion on the movement thereof resulting from movement of said carried by said cam means.

15. A machine as defined in claim 2 comprising a wheel dresser carried by said base at one end thereof,

a traverse device connected to said wheel support,

and releasable coupling means adapted to couple said lead slide to said wheel support for movement in unison, and to uncouple said lead slide and wheel support to provide for movement of said wheel slide relative to said lead slide into position adjacent said dresser.

16. A machine as defined in claim 15 comprising a second traverse device on said base connected to said lead slide operable to traverse of said lead slide and wheel support in unison when said coupling means is in coupling relation.

17. A machine as defined in claim 16, said lead slide being positioned on said base at the side of said wheel support opposite said dresser,

said coupling means comprising an elongated coupling members carried by said lead slide and extending to said wheel support, and

selectively operable means on said wheel support engageable in coupling relation with said elongated member. 18. A machine as defined in claim 17 comprising means for adjusting the length of said elongated member to adjust the spacing between said lead slide and said wheel support.

19. A machine as defined in claim 16, a crowning slide mounted on said lead slide for movement relative thereto in a direction perpendicular to the direction of movement of said wheel support and lead slide on said base,

sine bar mechanism on said crowning slide, means connecting said sine bar mechanism to said work support for rotating said work support, and

crowning cam means interposed between said slides and operable to move said crowning cam back and forth during each traverse stroke of said Wheel sup port.

20. A machine as defined in claim 19, said crowning cam means comprising a rotary cam carried by said lead slide,

adjustable cam actuating means carried by said base,

and

a cam follower means carried by said crowning slide,

said cam follower means comprising a pair of followers engaging opposite sides of said cam, said cam having a constant transverse dimension through its axis of rotation to provide for firm engagement with both followers at all times.

References Cited UNITED STATES PATENTS 945,467 1/ 1910 Landis. 2,066,220 12/1936 Orcutt 51-52 X 2,998,678 9/1961 Belock et al. 5152 2,804,734 9/1957 Mentley et a1. 51232 JAMES L. JONES, IR., Primary Examiner 

